In the 1970s, he emerged as one of the most prolific and popular recording artists in Jamaica. He released a number of self-produced singles on his African Museum(JA) label, formed in 1973 with Errol Dunkley. Much of Isaacs' output reflected the 'conscious' themes of Roots Reggae, but Isaacs was equally adept at interpreting more mainstream Lovers Rock material. His hits include "My Only Lover", "Sinner Man" and "Mr. Cop", recorded at Lee Perry's Black Ark Studio.

A period in the 1970s with the GG's label and its producer Alvin Ranglin produced hits like "Border" and "Number One". Many consider his best music to be from the various producers and labels he recorded with in the 1970's, with rootsier songs like 'Slave Master' from the classic 'Mr Isaacs' album (1977)contrasting with the optimism of songs like 'Love is Overdue' and the beautiful, moving 'Loving Paup...